- Jul 06, 2017 -

Knowledge of headset type classification

The headset is categorized according to the type of drive (transducer) and its way of wearing.

1.1 Drive technology

1.1.1 moving coil type headset is the most common and most common headphones, and its drive unit is basically a small moving coil speaker, by the permanent magnetic field in the voice coil drive connected with the vibration Membrane vibration. Moving coil headset efficiency is relatively high, mostly for the audio on the headphone output driver, and reliable and durable.

1.1.2 Magneto-like headphones such as magnetic head drive similar to the narrow plane speaker, it will be embedded in the voice coil into the thin diaphragm, like a printed circuit board, you can make the average distribution of driving force. The magnet concentrates on one or both sides of the diaphragm (push-pull), and the diaphragm vibrates in the magnetic field it forms. And other magnetic headphones diaphragm without electrostatic earphone diaphragm as light, but there is the same large vibration area and similar sound quality, because of its diaphragm quality and magnetic circuit structure, so that its efficiency is low, as moving coil headset easy to drive The YAMAHA HP2 headphones are a representative of the magnetic headphones.

1.1.3 Electrostatic electrostatic headphones are light and thin diaphragm, polarized by high DC voltage, the energy required for polarization by the AC conversion, but also battery-powered. The diaphragm is suspended in an electrostatic field formed by two fixed metal plates (stators). When the audio signal is loaded on the stator, the electrostatic field changes and vibrates the diaphragm. The single stator can also drive the diaphragm, but the double stator's push-pull form is less distorted. The electrostatic headset must use a special amplifier to convert the audio signal into a voltage signal of several hundred volts. The solution can also be driven by connecting the transformer at the output of the power amplifier. This solution is widely available in the smart headphones of the 1960s and 1970s Adopted, it is the cost of compromising the cost of an electrostatic headphone amplifier, and the signal quality does not reach the level of specially designed electrostatic headphone amplifiers. Electrostatic headset structure of precision, high material requirements, and more for manual assembly debugging, it is expensive. Static headphones due to the limited distance between the stator and the diaphragm, the diaphragm limit is limited, can reach the sound pressure level without moving coil headset, but it's fast response, to reproduce a variety of small details, distortion Very low

1.1.4 electret electret headphones also known as fixed electrostatic headphones, its diaphragm itself is polarized or polarized by the diaphragm of the electrostatic field of polarization, do not need special equipment to provide polarization Voltage. The electret headphones feature most of the features of the electrostatic headphones, but the electret will gradually depolarize, the volume becomes smaller, the performance is reduced, the need to replace the diaphragm, its life is generally about 5-10 years.

1.1.5 Wireless Headphones and Cordless Headphones They consist of two parts, a signal transmitter and a headset (usually moving coil) with signal receiving and amplifying devices. The transmitter is connected to the signal source, or it can be accessed before the transmitter to improve the sound quality and adjust the tone.

Wireless headset generally refers to the infrared transmission of the signal headset system, cordless headset refers to the use of radio waves transmission signal headset system. Infrared headphones operating frequency from a few KHz to several MHz, the effective distance of about 10 meters, the headset to be within the visual range; radio headphone operating frequency VHF 130MHz-200 MHz, UHF 450 MHz-900MHz, most cordless headphones work in UHF , Can be transmitted up to 100 meters, you can bypass the obstacles. Two or more wireless / cordless headphones may interfere with each other, so choose the best time to choose a number of operating frequency of the variety or professional headset brand production of anti-interference ability of products, for cordless headphones, working in UHF ratio The interference on the VHF may be small. These two headphones have background noise, more advanced models are used to reduce the noise of the technology. Now SENNHEISER and AKG companies have digital transmission technology using wireless / cordless headset products, the so-called digital transmission is the transmitter built-in A / D conversion line, the audio analog signal into digital signals and launched out, headset built-in D / A conversion line The received digital signal is reduced to an analog signal. Digital signal transmission anti-interference ability, the signal loss is very small, the background noise is very low, sound quality and D / A and A / D conversion accuracy, such as AKG HEARO888 UHF cordless headset with 18bit, 44.1KHz conversion accuracy, Can achieve the CD sound quality level of high fidelity and large dynamic. Select the wireless / cordless headset also note that the battery life, generally should not be less than 8 hours.

1.2 headset structure headset shell and ear pad design is linked, the shell is closed headphones generally around the ear ear, the shell is open headphones common ear ear ear. Earplugs are divided into plug and heel, the latter with a rubber jacket or seal, can provide good sound insulation performance.

1.2.1 Open headphones The headphones are open and the ear pads can be around the ear or the ear. Open headphones are lightweight, comfortable to wear, natural sound, no pressure, low frequency accuracy. Because it is open, the sound will leak to the outside world, the outside noise will enter, when the sound is relatively large, the sound of the leak is more serious, the outside world can hear, you can also feed the microphone. If the headset is open to a high degree, you can hear the other side of the unit issued a sound, the formation of a certain feedback, making a sense of natural.

There are not often mentioned semi-open headphones, before people have said above the open headphones called semi-open headphones, because although the headset shell is open, but the earmuffs are not completely open. Now talking about semi-open headphones is the opening of the headset is selective, that is, only certain frequencies open to other frequencies are closed, or in a certain direction is open in the other direction is closed.

1.2.2 closed headphones headphones are closed, the ear cushions close to the ears or hold the ears, to prevent external sound into the earphones of the ear type of the type of around the ear, the sound of the leak is Little or no leakage, in the professional use of a lot of monitoring. The sound is generally very clear, rich in detail, low frequency response is very good, but because of the low frequency may be in the shell and diaphragm formation of the cavity repeatedly caused by low-frequency uplift, low frequency may be too much, or oppression, Most people have closed headphones without open headphones comfortable.

Earphones are not much to say here, high-end monitor earplugs are listening tube, the frequency response is based on the individual's auditory curve design, the sound is very satisfactory, the use of improper damage may be hearing.